With more data now available to understand the mechanisms behind the changes, I thought I'd take a look at the effect of these changes on rail staff, who are entitled to Privilege fares (Priv), with 75% off flexible fares. Obviously, this is a niche aspect that is not applicable to the vast majority passengers.
Currently, from London to Edinburgh, a Priv Super Off Peak Single costs £21.75 for fully flexible travel within the applicable time constraints.
Under the new regime, this fare will be abolished - superficially being replaced by the 70min Flex Single, at a fixed rate of £25.90.
Immediately, this can be seen to be a 19% increase in the fare - and for a substantially inferior product.
However, despite this fixed fare, it is actually an "Advance" product that is directly affected by public quotas.
The Priv ticket type is "DMP". Essentially, if the public fare is at or below the DMP 70min Flex rate of £103.70, a Priv 70min Flex Single will be available at a fixed rate of £25.90. i.e. The proper Priv rate only applies when the public fare is exactly £103.70. The lowest public fare for a 70min Flex is £51.20, but the Priv rate remains £25.90 - a discount of just 49%, rather than the usual 75%.
When the public 70min Flex fare exceeds £103.70, the Priv rate ticket ceases to be available - see screenshot. The result is that it becomes necessary to purchase the Anytime ticket at £48.45, which is a 123% increase in the fare payable.
Whilst, for now, this scheme can easily be worked around by those in the know, if/when it is rolled out wholesale, it will massively affect discretionary travel. Because of the discounted fares available, rail staff tend to be more spontaneous and will often make discretionary journeys at short notice. It would become a choice of booking miles in advance to only pay 20% more than now, for substantially less flexibility, or wait - and have to pay more than double the current fare. In that case, discretionary journeys are less likely to be made, meaning the railway loses out. I can say for certain that neither of my most recent trips on LNER would have taken place had this new regime been in place.